Decreased max opened files ulimit inside salt containers.

This change is related to: https://github.com/saltstack/salt/issues/18569

Change-Id: Ifc65479442ec52a48c2a47d645cbe47d125f36fb
diff --git a/src/com/mirantis/mk/SaltModelTesting.groovy b/src/com/mirantis/mk/SaltModelTesting.groovy
index 5434fff..5bba09b 100644
--- a/src/com/mirantis/mk/SaltModelTesting.groovy
+++ b/src/com/mirantis/mk/SaltModelTesting.groovy
@@ -34,7 +34,7 @@
     dockerMaxCpusOption = "--cpus=${dockerMaxCpus}"
   }
 
-  img.inside("-u root:root --hostname=${masterName} ${dockerMaxCpusOption}") {
+  img.inside("-u root:root --hostname=${masterName} --ulimit nofile=4096:8192 ${dockerMaxCpusOption}") {
 
     def is_mk_ci
     try {